Electrical terminals incorporating break-away pins



Aug. 16, 1966 H. DOZIER 3,267,205

ELECTRICAL TERMINALS INCORPORATING BREAK-AWAY PINS Filed Aug. 10, 1965 INVENTOR I /ILL/AED 002/512,

M m and $2.

ATTORNEYS R 3,267,205 Patented August 16, 1966 3,267,205 ELECTRICAL TERMINALS INCORPORATING BREAK-AWAY PiNS Hilliard Dozier, Cincinnati, Ohio, assignor to U.S. Terminals, Inc., Cincinnati, Ohio, a corporation of Ohio Filed Aug. 10, 1965, Ser. No. 478,642 11 Claims. (Cl. 174-153) This invention relates to electrical terminals of the type employed in the electronics industry, and ha to do more particularly with terminal assemblies composed of preassembled electrodes and insulators, the electrodes being provided with break-away stems by means of which the terminal assemblies may be readily secured to a terminal board or chassis.

Terminals constructed in accordance with the instant invention embody the locking principle set forth in Dozier Patent 3,095,470, issued June 25, 1963, and entitled Insulated Electrical Terminal Construction. In accordance with this patent, each terminal is composed of an elongated electrode or center pin and an insulator which are pre-assembled so as to comprise a one-piece unit in the hands of the user. The insulator, which is usually formed from a dielectric material, such as Teflon, has a cylindrical body portion terminating at one end in an enlarged head, the body portion being of the size such that it may be readily fitted into an opening in a terminal board with the enlarged head of the insulator seated against one face of the board and the cylindrical body projecting outwardly from the opposite face. The electrode, which is fitted into the insulator from the end opposite the enlarged head, is displaced axially in the direction of the enlarged head, such displacement causing an enlarged body part of the electrode to expand the cylindrical body of the insulator radially outwardly, thereby effecting a positive lock between the terminal and the terminal board. Such construction does not rely on a press fit to secure the terminal to the board, and while it is possible to insert such terminal from either side of the board it is nonetheless necessary that sufficient working room be available on the opposite side of the board to permit a tool to engage the electrode, and displace it axially into the insulator. Since the electrode is being displaced in the direction of the enlarged head of the terminal, a support must be provided to hold the head ofthe insulator in contact with the terminal board during the attaching operation. The necessity for engaging the electrode on one side of the terminal board and the head otthe insulator on the other has presented problems where space limitations preclude ready access to both sides of the terminal board.

Accordingly, in accordance with the instant invention, a terminal construction is provided wherein the electrode may be engaged with the terminal board and locked in place entirely from one side of the terminal board without the necessity of supporting or otherwise engaging any part of the terminal lying on the opposite side of the board.

A principal object of the instant invention is the provision of a terminal comprising an elongated electrode surrounded by an insulator having a cylindrical body portion and an enlarged head at one end, the electrode including a break-away stemportion adapted to project outwardly beyond the enlarged head of the insulator, whereby when the body of the insulator is inserted in an opening in the terminal board the electrode may be displaced axially by means of the break-away stem which breaks off when the parts assume their final position of use.

A further object of the invention is the provision of a terminal construction incorporating a break-away stem formed either as an integral extension of the electrode or as a separate part adapted to be detachably connected to the electrode.

A further object of the instant invention is the provision of a terminal construction embodying a break-away stem by means of which the terminal may be attached to a terminal board, irrespective of whether such terminal is of the standoff or feed-thru variety, or comprises a binding post terminal having a displaceable knob by means of which a wire or connector is secured to the electrode. Similarly, the break-away stem construction of the instant invention may be utilized with terminals provided with sockets for receiving a test probe, banana plug or phone tip.

The foregoing objectives, together with others which will appear hereinafter or which will be apparent to the skilled worker in the art upon reading this specification, are accomplished by those constructions and arrangements of parts of which certain exemplary embodiments as shall now be described.

Reference is now made to the accompanying drawings wherein:

FIGURE 1 is a plan view of an electrode incorporating a break-away stem.

FIGURE 2 is a vertical sectional view illustrating the manner in which the electrode is associated with its insulator and the assembly inserted in a terminal board prior to locking displacement of the electrode.

FIGURE 3 is a vertical sectional view similar to FIG- URE 2 but illustrating the parts in the final assembled condition, the electrode having been axially displaced by means of the stem engaging tool shown in dotted lines.

FIGURE 4 is a vertical sectional view illustrating the completely assembled terminal with the stem broken away.

FIGURE 5 is an exploded side elevational view of an electrode for a stand-oft type of terminal, together with its insulator cap.

FIGURE 6 is a vertical sectional view illustrating a fully assembled stand-oft terminal incorporating the electrode and cap of FIGURE 5.

FIGURE 7 is a vertical sectional view of a modified form of insulator cap.

FIGURE 8 is a vertical sectional view illustrating a modified electrode construction.

FIGURE 9 is an exploded vertical sectional view illustrating an electrode construction in which the break-away stem is threaded into the electrode.

FIGURE 10 is a vertical sectional view illustrating the use of a break-away stem in conjunction with a binding post terminal having a spring biased locking knob.

Referring first to FIGURE 1 of the drawings which illustrates an exemplary electrode of the feed-thru type, the electrode or terminal pin 1 is formed from a conductive metal and machined to define a tapered bore engag ing shoulder or barb 2 and a preferably somewhat larger tapered expansion shoulder 3 which terminates in an enlarged body part 4 .at least a portion of which is milled or knurled, as at 5. An annular cap 6 covers the end of the body part and mounts a post or pin 7 to which a wire or connector may be secured. At its opposite end the electrode has a distal portion 8 also adapted to receive a wire or connector; and in accordance with the instant invention a break-away stem 9 is formed in prolongation of the distal portion 8, the stem being separated by an annular groove 10 which provides a line of weakening so that the stem may be subsequently broken away from the electrode.

The electrode is adapted to be pre-assembled to an insulator 11 which, as seen in FIGURE 2, has a cylindrical body portion 12 terminating at one end in a beveled edge 13 and at its opposite end in an enlarged head 14. A central bore 15 extends through the insulator, into which the electrode 1 is inserted from the end opposite the enlarged head. The parts are preferably preassembled and supplied to the user in the condition illusbarbed shoulder 2 is in biting engagement with the cylindrical body of the insulator but with the enlarged body part 4 lying outside the confines of the central bore. The dimensioning of the parts is such that the user may readily insert the cylindrical body portion 12 of the insulator into an opening 16 in a terminal board or chassis 17 to which the terminal is to be attached. If the terminal were to be attached in conventional fashion it would be necessary to support the enlarged head 14 on one side of the chassis and then displace the electrode axially toward the enlarged head of the insulator from the opposite side of the terminal board. As opposed to such procedure, in accordance with the instant invention the axial displacement of the electrode is effected by pulling on the break-away stem 14 using a tool 18 diagrammatically illustrated in FIGURE 3, the tool being of the type disclosed in Gookin United States Patent No. 2,582,248, issued January 15, 1952, the tool having a nose 19 surrounding an opening 20 in which the stern of the electrode is inserted, the stem being engageable by one or more axially displaceable clamping jaws indicated at 21, which are adapted to engage the stem 9 and move it in the direction of the arrow A. With the tool engaged over the stem 9 and distal portion 8 of the electrode in the manner illustrated, it will be evident that the nose 19 will bear against the enlarged head of the insulator, thereby maintaining it seated against the terminal board 17 as the electrode is displayed so as to bring the enlarged body part 4 within the confines of the cylindrical body portion 12 of the insulator. The body portion of the insulator is thus caused to expand radially outwardly in the manner illustrated in FIGURE 3, thereby locking the terminal in place. As will be evident from FIG- URE 3, the final position of the electrode relative to the insulator is established when the shoulder 2 of the electrode contacts the nose 19 of the tool which enters into bore 15 in the insulator in the manner illustrated. By continuing the application of the pulling force to the stem 9, with the shoulder 2 serving as a stop holding the body of the electrode against further axial movement, the stern caused to break-away from the distal end of the electrode along the line of weakening defined by the annular groove 10. The stem thus separates from the electrode in the manner illustrated in FIGURE 4, thereby leaving the distal position 8 projecting outwardly from the insulator so as to provide a post or pin to which a wire or conhector may be secured. The barbed shoulder 2 lies within the confines of the enlarged head of the insulator and coacts with the cap 6 to maintain the body portion of the insulator in its radially expanded condition. The resultant terminal is of the feed-thru type having a post at each end.

If it is desired to provide a stand-ofi? type of terminal having a single post, the electrode illustrated in FIG- URE may be employed. As seen therein, the cap 6 supports a barb-shaped projection 22 which is adapted to be inserted in the socket 23 of an insulator cap 24 which will be preferably formed from the same material as the insulator itself. Preferably the annular cap 6 will be only slightly larger in diameter than the diameter of the bore in the insulator, with the insulator cap 24 of somewhat larger diameter than the annular cap 6. When the parts are assembled in the manner illustrated in FIGURE 6, the annular cap 6 will be sandwiched between the end of the insulator and the undersurface of the insulator cap, with the insulator and insulator cap projecting outwardly beyond the periphery of the electrode cap 6 to thereby form a shield. If desired, the insulator cap 24 may be provided with a circular recess 25, as seen in FIGURE 7, the recess 25 being of a size to receive the cap 6 and hence juxtapose the marginal edge of the insulator cap to the end edge of the insulator body. Alternatively, the insulator cap could be adhea V sively secured to the end of the electrode or to the end of the insulator body.

FIGURE 8 illustrates a modification of the invention 7 wherein the central bore in the insulator has a first section 26 which is of a larger diameter than the remaining section 26a, whereby more readily accommodating the very much thinner distal portion 8a of the electrode. It may be observed that the relative dimensioning of the parts may vary widely depending upon the requirements of use. For example, the central bore in the insulator may have one, two or more sections of varying diameter and length, depending upon the dimensioning of the barb and enlarged body part of the electrode. than one barb may be employed, although one of the barbs or an enlarged shoulder or stop will be positioned so as to lie sufiiciently close to the outer surface of the enlarged head of the insulator so that it can be contacted by the nose of the tool to provide an abutment effective to hold the electrode while the jaws of the tool are applying breaking force to the stem. The break-away stem need not be of the same diameter as the distal portion of the electrode to which it is secured.

While thus far the exemplary electrodes illustrated have had the break-away stem formed as an integral extension of the electrode itself, it is also within the spirit and purpose of the invention to form the break-away stem as a separate part. Thus, as seen in FIGURE 9 the stem 9 is provided at one end with threads 27 by means of which the stem may be secured to the internally threaded socket 28 formed in the body of the electrode. In the embodiment. illustrated, the threaded socket 28 lies at the bottom of a somewhat larger diameter socket 29 which may be of the size to receive a test probe, banana plug or a phone tip. Test jack terminals are quite frequently employed in various electrical components to facilitate testing of the circuits and other operating parts. It is to be understood, however, that the use of a threaded stem is not limited to test jack terminals but rather may be utilized in conjunction with any terminal the electrode of which is capable of being provided with a threaded socket.

When the threaded stem is engaged in the threaded socket, it will be evident that the electrode may be attached to the insulator and the assembly connected to a terminal board in the manner previously described, excepting in this instance the end of the electrode acts as a shoulder or stop for the nose of the tool. When the electrode is sea-ted in its final position of use and its movement relative to the insulator has been stopped, the continued pulling action of the jaws of the tool on the stem will result in stripping of the threads securing the stem in the socket 28 and the stem will thereby be released. In order to facilitate the stripping action, a relatively small number of threads will be employedfour full threads having been found to be particularly suited in most instancesand the threads should be relatively shallow so as to more readily strip when stripping force is applied.

FIGURE 10 illustrates the use of a threaded pin in conjunction with a binding post terminal of the type disclosed in Dozier Uni-ted States patent application Serial No. 477,128, filed August 4, 1965, and entitled Spring Loaded Electrical Terminal, such terminal incorporating a knob member 30 biased by means of spring 31 to normally surround the cross-drilled opening 32 in the electrode. When the knob is displaced upwardly the opening 32 is exposed for the insertion of a wire or a connector, whereupon the knob is released and enters into clamping engagement with the wire or connector, clamping it between the knob and the enlarged head of the insulator. In the embodiment illustrated, the threaded end 27 of stem 9 is received in threaded socket 28 in the distal end of the electrode which, in this instance, has a larger socket portion 33 .for receiving a test probe or the like. It will be evident that when the terminal If desired, more a 1 5 is fitted to a terminal board, the electrode may be displaced axially in the direction of the head 14 of the insulator by means of the stem 9 with the stem engaging tool seated against the outermost end of knob 30. Once the electrode has been axially displaced and assumes its assembled position relative to the insulator, the stem will be detached by stripping the threads securing the stem in socket 28. In this connection, the dimensioning of the parts will be such that the uppermost end of the electrode, indicated at 34, will be contacted by the nose of the tool and hence will provide a positive stop which will hold the electrode against axial movement as the jaws of the tool continue to pull on the stem 9.

It will be evident that where the stem is formed as a separate member it can be secured to the electrode other than by a threaded connection. For example, the stems may be attached by means of solder or a cementitious material having sufficient bond-ing strength to permit the assembly of the parts and yet capable of being ruptured when additional force is applied. It also will be evident that while a shoulder or stop is required to arrest axial displacement of the electrode where the insulator is of distortable character, such stop is not required where the insulator is sufliciently rigid tomaintain the electrode against further axial displacement once the electrode cap has seated against the end of the insulator.

Additional modifications may be made to the invention without departing from its spirit and purpose. Various modifications have already been set forth and others undoubtedly will occur to the skilled worker in the art upon reading of this specification; and it is not intended that the invention be limited other than in the manner set forth in the claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. For use in an electrical terminal, an elongated electrode having a body including a tapered expansion shoulder in advance of an enlarged cylindrical body part, an' essentially fiat cap portion lying beyond said enlarged body part on the side thereof opposite said expansion shoulder, an elongated stern detachably connected to said body, said stem projecting outwardly from said electrode body in advance of said expansion shoulder in prolongation of the length of said electrode, and a stop forming shoulder of larger diameter than said stern 1ying in advance of said expansion shoulder.

2. The electrode claimed in claim 1 wherein said elongated stem is integrally formed with said electrode and demarked from the body thereof by an annular recess defining a line of weakening by means of which said stem may be separated from the body of said electrode.

3. The electrode claimed in claim 1 wherein said electrode body has a socket formed therein, and wherein one end of said elongated stem is detachably secured in said socket.

4. The elect-rode claimed in claim 3 wherein the elongated stem is in threaded engagement with said socket.

5. An electrical terminal comprising an insulator and an electrode, said insulator being formed from a distortable dielectric material and having a cylindrical body terminating at one end in an enlarged head, and an axial bore extending through said insulator, said electrode having an elongated body inserted in said axial bore from the free end of the cylindrical body portion thereof, a stop forming barbed shoulder the maximum diameter of which is greater than the diameter of the axial bore in said insulator, a tapered expansion shoulder lying beyond said barbed shoulder, said expansion shoulder terminating in an enlarged body part having a diameter greater than the diameter of said axial bore, an essentially flat cap portion lying beyond said enlarged barbed shoulder, and an axially extending stem detachably connected to said distal portion and extending outwardly beyond the enlarged head of'said insulator, the axial spacing of said barbed shoulder and said enlarged body part relative to each other and to said cap portion being such that when the cylindrical body portion of the insulator is inserted in a terminal receiving opening in a terminal board with the enlarged head seated against one face of the terminal board, the projecting stem may be utilized to displace the electrode axially so as to seat the said cap portion against the free end of the cylindrical body portion of the insulator, with the enlarged body part of the electrode lying within the said axial bore on the side of the terminal board opposite the enlarged head so as to expand the cylindrical body of the insulator radially outwardly, the stop forming barbed shoulder being in biting engagement with the insulator adjacent the outer .surface of the enlarged head thereof and coacting with said cap portion to hold the insulator in axial compression, whereby the terminal is securely locked to the terminal board, whereupon the projecting stern may be detached from the electrode by means of a tool having a nose portion lying in advance of jaw means operative to exert a pulling force axially of said stem in the direction of the enlarged head of the insulator, axial movement of the electrode relative to the insulator being stopped when the said stop forming shoulder contacts the nose portion of the tool.

6. The terminal construction claimed in claim 5 wherein said stem is formed as an integral extension of said electrode and is separated from said distal portion by an annular line of weakening.

7. The terminal claimed in claim 5 wherein said electrode has a projection extending outwardly from the cap portion thereof, and wherein an insulator cap is fitted over said projection.

8. The terminal construction claimed in claim 7 wherein said insulator cap is of a diameter greater than the diameter of the cap portion of said electrode and has a recess in the under surface thereof of a size to receive the cap portion of the electrode.

9. An electrical terminal composing an insulator and an electrode, said insulator being formed from a distortable dielectric material and having a cylindrical body terminating at one end in an enlarged head, an axial bore extending through said insulator, said electrode comprising an elongated pin inserted in said axial bore from the end thereof opposite said enlarged head, said electrode having an enlarged body portion positioned to lie within the confines of said insulator when the terminal is attached to a terminal board, an elongated stem detachably connected to said electrode, said stem project ing outwardly from said electrode in prolongation of its length and extending outwardly beyond the enlarged head of said insulator, said electrode including a shoulder lying beyond the enlarged body portion of said electrode in the direction of said stem and positioned to act as a stop, whereby when said stem is engaged by a tool having a nose portion lying in advance of jaw means operative to exert a pulling force axially of said stem in the direction of the enlarged head of said insulator, axial movement of the electrode relative to the insulator will be stopped when the said shoulder contacts the nose portion of the tool.

10. The electrical terminal claimed in claim 9 wherein said shoulder comprises an annular barb adapted to enter into biting engagement with the axial bore in said insulator.

11. The electrical terminal claimed in claim 9 where- 7 8 in said. shoulder is defined by an end of the electrode FOREIGN PATENTS surrounding a stem receiving socket. 131,893 11/1919 Gmat Britaim 862,797 3/ 1961 Great Britain.

References Clted by the Examluer v 916,161 1/1963 Great Britain.

UNITED STATES PATENTS 5 1 54 1 2/1951 'Keama LARAMIE E. ASKIN, Primary Examiner.

3,047,181 7/1962 Heidenwolf 85-78 X 3,095,470 6/1963 Dozier 174166X 

1. FOR USE IN AN ELECTRICAL TERMINAL, AN ELONGATED ELECTRODE HAVING A BODY INCLUDING A TAPERED EXPANSION SHOULDER IN ADVANCE OF AN ENLARGED CYLINDRICAL BODY PART, AN ESSENTIALLY FLAT CAP PORTION LYING BEYOND SAID ENLARGED BODY PART ON THE SIDE THEREOF OPPOSITE SAID EXPANSION SHOULDER, AN ELONGATED STEM DETACHABLY CONNECTED TO SAID BODY, SAID STEM PROJECTING OUTWARDLY FROM SAID ELECTRODE BODY IN ADVANCE OF SAID EXPANSION SHOULDER IN PROLONGATION OF THE LENGTH OF SAID ELECTRODE, AND A STOP FORMING SHOULDER OF LARGER DIAMETER THAN SAID STEM LYING IN ADVANCE OF SAID EXPANSION SHOULDER.
 9. AN ELECTRICAL TERMINAL COMPOSING AN INSULATOR AND AN ELECTRODE, SAID INSULATOR BEING FORMED FROM A DISTORTABLE DIELECTRIC MATERIAL AND HAVING A CYLINDRICAL BODY TERMINATING AT ONE END IN AN ENLARGED HEAD, AN AXIAL BORE EXTENDING THROUGH SAID INSULATOR, SAID ELECTRODE COMPRISING AN ELONGATED PIN INSERTED IN SAID AXIAL BORE FROM THE END THEREOF OPPOSITE SAID ENLARGED HEAD, SAID ELECTRODE HAVING AN ENLARGED BODY PORTION POSITIONED TO LIE WITHIN THE CONFINES OF SAID INSULATOR WHEN THE TERMINAL IS ATTACHED TO A TERMINAL BOARD, AN ELONGATED STEM DETACHABLY CONNECTED TO SAID ELECTRODE, SAID STEM PROJECTING OUTWARDLY FROM SAID ELECTRRODE IN PROLONGATION OF ITS LENGTH AND EXTENDING OUTWARDLY BEYOND THE ENLARGED HEAD OF SAID INSULATOR, SAID ELECTRODE INCLUDING A SHOULDER LYING BEYOND THE ENLARGED BODY PORTION OF SAID ELECTRODE IN THE DIRECTION OF SAID STEM AND POSITIONED TO ACT AS A STOP, WHEREBY WHEN SAID STEM IS ENGAGED BY A TOOL HAVING A NOSE PORTION LYING IN ADVANCE OF JAW MEANS OPERATIVE TO EXERT A PULLING FORCE AXIALLY OF SAID STEM IN THE DIRECTION OF THE ENLARGED HEAD OF SAID INSULATOR, AXIAL MOVEMENT OF THE ELECTRODE RELATIVE TO THE INSULATOR WILL BE STOPPED WHEN THE SAID SHOULDER CONTACTS THE NOSE PORTION OF THE TOOL. 